Yes, I think the Welsummers in Australia may differ from those in the US. I noticed that your chicks have white legs and feet, and here the standard calls for yellow. Who knows what other differences there might be between the strains, which makes clues for sexing a bit more difficult. I think your #1 chick is all boy, but maybe there's room to hope for pullets for the others, especially #3 and #4! Sending girly thoughts your way!